This invention is directed to a method of producing fully encircling, curved leg elastics. The method involves placing a pair of elastic ribbons on a pair of curved pucks, each puck having a curved surface adjacent a preferably curved top surface, and subsequently applying the elastic ribbons to a substrate.
Pant-like absorbent garments, such as adult incontinence wear, as well as infant and children""s diapers, swim wear and training pants, typically include a pair of leg openings having an elastic portion around each leg opening. The elastic portions are intended to fit snugly around a wearer""s legs to prevent leakage from the garment.
Various technologies are known for applying leg elastics to such articles. For example, one technology involves bonding a continuous loop to a substrate. However, producing a supply of continuous loops of elastic strands is more costly and cumbersome than providing a supply of a continuous length of elastic ribbons.
Articles which incorporate conventional elasticized margins and conventional barrier flap configurations at their leg openings have, however, exhibited various shortcomings. For example, it has been difficult to avoid pressure-induced marking of the wearer""s skin and difficult to maintain the desired gasketing of the leg openings when the articles are being worn. Even when the leg openings are fitted with an elastomeric material or otherwise elasticized, it has been difficult to maintain contact between the leg opening and the wearer""s body for an effective containment of urine and feces. As a result, there has been a continued need for improved containment structures at the leg regions of the absorbent articles.
There is a need or desire for a process for making comfortable, gasket-like leg elastics that are aesthetically pleasing and can be applied in a high-speed application.
The present invention is directed to a method of applying curved leg elastics to pant-like absorbent garments using pucks with curved surfaces. The result is a comfortable, flexible, aesthetically pleasing leg opening. Furthermore, the resulting leg opening is form-fitting and acts like a gasket.
Apparatus that can be used for carrying out the invention includes a pair of rotating devices with a plurality of curved pucks attached to a periphery of each of the rotating devices, a pair of orbital tuckers, a pair of bonding devices and a pair of cutting devices. The curved pucks have a curved surface around which an elastic ribbon is stretched.
In carrying out the invention, each elastic ribbon of a pair of elastic ribbons is guided through one of the cutting devices where the ribbon is perforated for later separation into discrete pieces, then onto one of the pucks on one of the rotating devices. The elastic ribbon is guided onto the pucks such that a portion of the elastic ribbon overhangs the edge of a first curved surface of the puck. Tension in the elastic ribbon causes the overhanging portion to fold over onto an adjacent, second curved surface of the puck. The elastic ribbon is deflected to conform to the first curved surface of the puck by an orbital tucker, and separated into discrete pieces at the perforation by the orbital tucker as it passes between adjacent pucks. Alternatively, the elastic ribbon may already be in discrete lengths prior to carrying out the method of the invention. A vacuum is used to hold the elastic ribbon in place on the puck. The rotating device continues to advance the puck toward the bonding device. While the rotating device rotates, the device changes the machine direction radial spacing of the pucks to provide proper spacing of the elastics for placement on the substrate. Once the puck is in contact with the substrate, the portion of the elastic ribbon folded onto the second curved surface of the puck is bonded to the substrate. The substrate is typically a liner of an absorbent garment.
The method of the invention can be used in high-speed applications, namely applications running at linear speeds of 600 feet per minute or greater. More curved pucks can be located on the periphery of the rotating device to enable a more expedient process. The rotating device can be adjusted to change pitch or machine direction spacing between adjacent pucks from the point of application of the elastic ribbons to the pucks to the point where the elastic ribbon is transferred and bonded to the substrate.
The substrate may be stretchable or extensible, thereby providing great flexibility and enabling the elastic ribbons to be applied at low tension. Furthermore, stretchability and/or extensibility of the substrate provide for a larger leg fit range.
The resulting product is an absorbent garment having a comfortable, aesthetically pleasing, finished look about the leg openings. This method can also be used to apply curved standing leg cuffs and/or curved leak guard flaps.
With the foregoing in mind, it is a feature and advantage of the invention to provide a method of applying curved leg elastics to an absorbent garment.
It is another feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in gasket-like leg openings.
It is yet another feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in form-fitting leg openings.
It is a further feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in comfortable and aesthetically pleasing leg openings.